When your on the Eiffel Tower online ticket site can you purchase tickets with no set time and still use them to get up the Tower. Only time they had available for June 12 was 10 PM. Kind of late.
No Thomas you can only prepurchase timed slot tickets and frankly if there are any left I would take them if you don't want to wait in long lines or take the stairs. They only sell a few for each time slot , the rest of the visitors will either purchase a tour that includes the Eiffel Tower ( can be a bit pricey) or they will wait, or they will take the stairs.